Just to share a sparks in my head, if we asking ourselves, what are the main difference of the card game? Eventually it is a game, and it is tied to the play of the game. If the block chain technology is to maintain and distribute the ability of the cards, where else the art is the flavour of it.
Both of us are drinking soda (the game play) but I prefer grapes and opponent is prefer apple.. eventually I am playing my grape flavoured card against your apple flavoured card, however under the same game rules it makes more fun.
Further more, with this ability of alt arts will promote more "value" of the collecting card. Which is the art creator to decide how many copies do exists in the system.
Anyway, this is just my sparks of idea. I will be delighted to see when I playing with my son, he could have his own art fighting against his father own collection.